diff --git a/dockerfiles/geo-ci b/dockerfiles/geo-ci
index c98bca2..5101114 100644
--- a/dockerfiles/geo-ci
+++ b/dockerfiles/geo-ci
@@ -8,7 +8,7 @@ ARG RUST_VERSION
 ARG PROJ_VERSION
 
 FROM ghcr.io/georust/libproj-builder:proj-${PROJ_VERSION}-rust-${RUST_VERSION} as libproj-builder
-FROM rust:$RUST_VERSION-bullseye
+FROM rust:$RUST_VERSION-slim-bullseye
 
 ARG RUST_VERSION
 ARG PROJ_VERSION
diff --git a/dockerfiles/libproj-builder b/dockerfiles/libproj-builder
index cb34275..d98a741 100644
--- a/dockerfiles/libproj-builder
+++ b/dockerfiles/libproj-builder
@@ -3,7 +3,7 @@
 # Builds libproj from source
 
 ARG RUST_VERSION
-FROM rust:$RUST_VERSION-bullseye
+FROM rust:$RUST_VERSION-slim-bullseye
 
 ARG RUST_VERSION
 ARG PROJ_VERSION